4 BULLETIN 622, U. S. DEPARTMENT OF AGRICULTURE. 



detail, his conception of varieties was such as to establish most of 

 them upon a firm basis. His treatment of the larger groups, on the 

 other hand, was less satisfactory. He recognized hexastichon, 

 tetrastichum, intermedium, and distichum as his primary groups. 

 These are more fully discussed later. A third paper appeared in 

 1895, and in 1908, after his death, his son, M. Kornicke, published 

 a fourth treatment. Neither of these latter possesses the clearness 

 of the earlier papers, and they include many doubtful varieties. 

 Many of the additions were of hybrid origin and were unfixed at 

 the time of publication. Kornicke's failure in many instances was 

 due to the general lack of genetic information at that time. Recent 

 discoveries have made the purification of a type rather simple. For 

 instance, his subcomutum was selected from a mating of trifurcatum 

 and steudelii and was far from fixed. A constant variety of this 

 type is readily obtained from a cross of cornutum X pallidum or of 

 liorsfordianum X haxtoni. Many varieties attributed to Kornicke in 

 the key which follows were heterozygous forms with him which he 

 was never able to fix. Most of these have been recognized in this 

 publication, because fixed forms corresponding to the descriptions 

 have since been produced. 



In 1885, the year in which the " Handbuch des Getreidebaues " was 

 published, a paper by Voss appeared. A^oss follows Jessen (18.55) 

 and places all cultivated barleys under the single species Hordeum 

 sativum. Although his handling of the varieties is inferior to that 

 of Kornicke, his treatment of the larger groups is decidedly better. 

 He uses polystichon, distichon, and deftciens as his subspecies. He 

 indicates that deficiens is subject to the same variations as distichon 

 by subdividing it into dense and lax divisions. He substitutes in- 

 equale for the term tetrastichum of Kornicke, pointing out that there 

 is no such thing as a 4-rowed barley. 



Following Voss came Atterberg, who published various papers 

 between 1889 and 1899. In the latter year he advanced a new basis 

 of classification. He made four subspecies under Hordeum sativum 

 Jess., namely, commune, macrolepis, furcatum, and inerme. As 

 both the character of the outer glumes and the appendages to the 

 lemma were used, the result was rather involved and seems to offer 

 little compensation for so abrupt a departure. Atterberg's concep- 

 tion of the regular occurrence of the subfactors through each of 

 the groups gives evidence of a familiarity with a larger number of 

 varieties than had been accessible to previous taxonomists. His sys- 

 tem of uniform recurrence of names in his subgroups seems inad- 

 visable and likely to lead to confusion, even though, as he points 

 out, he uses only 33 terms to designate 188 forms, while Kornicke 

 used 78 terms to designate 74 varieties. 



